1. Field of the Invention
The present invention generally relates to a mechanism for controlling a timed function, such exposure time, in a camera.
2. Description of the Prior Art
Numerous mechanisms have been devised for controlling a timed function in a camera. For example, there are a variety of devices for controlling the closing of a shutter to vary the period of time light is allowed to reach film in the camera. The simpler types may have several shutter speed settings, such as 1/60, 1/125, and 1/250 sec. The speeds are set manually, such as by moving a lever or a pointer along a scale located on the camera housing. Other, automatic types rely on light measurement for controlling the closing of the shutter. Here, the speed of the shutter is electronically determined as a function of the level of scene light reflected back into the camera. Typically, a light integrating timing circuit is energized in synchronization with movement of a shutter opening blade to initiate the timing of an exposure interval. The timing circuit subsequently actuates a shutter closing blade to terminate the exposure interval after a time period established by the timing circuit in accordance with the level of scene light received by a photocell in the circuit.
Another mechanism for controlling a timed function in a camera is a self-timer or delayed action shutter release by which a photographer can include himself in a picture. When a shutter release is pressed, exposure does not take place, but is delayed for a pre-set time--long enough for the photographer to take a position in the picture. The delay is usually achieved by allowing a spring to unwind slowly under the retarding action of a train of gears.